U.S. patent application number 15/096550 was filed with the patent office on 2016-08-04 for powder primer composition and laminate using it.
This patent application is currently assigned to ASAHI GLASS COMPANY, LIMITED. The applicant listed for this patent is ASAHI GLASS COMPANY, LIMITED. Invention is credited to Jun HOSHIKAWA, Hitoshi SUSA, Noriharu TATE.
Application Number | 20160222219 15/096550 |
Document ID | / |
Family ID | 53371118 |
Filed Date | 2016-08-04 |
United States Patent
Application |
20160222219 |
Kind Code |
A1 |
HOSHIKAWA; Jun ; et
al. |
August 4, 2016 |
POWDER PRIMER COMPOSITION AND LAMINATE USING IT
Abstract
To provide a powder primer composition excellent in adhesion
properties and a laminate obtained by using it. The power primer
composition comprises a powder made of a reactive
ethylene/tetrafluoroethylene copolymer containing repeating units
(A) based on tetrafluoroethylene, repeating units (B) based on
ethylene, and repeating units (C) based on a monomer having an acid
anhydride residue and a polymerizable unsaturated bond, wherein
(C)/((A)+(B)) is from 1/10,000 to 5/100 by molar ratio; and a
powder made of an epoxy resin having an epoxy equivalent of from
500 to 2,700 and a softening point of at least 70.degree. C.;
wherein the mass ratio of the powder made of a reactive
ethylene/tetrafluoroethylene copolymer to the powder made of an
epoxy resin is from 99/1 to 80/20.
Inventors: |
HOSHIKAWA; Jun; (Chiyoda-ku,
JP) ; TATE; Noriharu; (Chiyoda-ku, JP) ; SUSA;
Hitoshi; (Chiyoda-ku, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASAHI GLASS COMPANY, LIMITED |
Chiyoda-ku |
|
JP |
|
|
Assignee: |
ASAHI GLASS COMPANY,
LIMITED
Chiyoda-ku
JP
|
Family ID: |
53371118 |
Appl. No.: |
15/096550 |
Filed: |
April 12, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2014/082312 |
Dec 5, 2014 |
|
|
|
15096550 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/38 20130101;
C09D 7/65 20180101; C09D 5/002 20130101; C09D 5/03 20130101; C09D
163/00 20130101; C09D 5/00 20130101; C09D 123/08 20130101; B32B
27/322 20130101; C09D 7/66 20180101; C09D 127/18 20130101; C09D
127/18 20130101; C08L 27/18 20130101; C09D 5/031 20130101; C09D
163/00 20130101; C08L 63/00 20130101 |
International
Class: |
C09D 5/00 20060101
C09D005/00; C09D 127/18 20060101 C09D127/18; C09D 5/03 20060101
C09D005/03 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 2013 |
JP |
2013-255660 |
Claims
1. A powder primer composition comprising a powder made of a
reactive ethylene/tetrafluoroethylene copolymer containing
repeating units (A) based on tetrafluoroethylene, repeating units
(B) based on ethylene, and repeating units (C) based on a monomer
having an acid anhydride residue and a polymerizable unsaturated
bond, wherein (C)/((A)+(B)) is from 1/10,000 to 5/100 by molar
ratio; and a powder made of an epoxy resin having an epoxy
equivalent of from 500 to 2,700 and a softening point of at least
70.degree. C.; wherein the mass ratio of the powder made of a
reactive ethylene/tetrafluoroethylene copolymer to the powder made
of an epoxy resin is from 99/1 to 80/20.
2. The powder primer composition according to claim 1, wherein the
average particle size is from 1 to 1,000 .mu.m.
3. The powder primer composition according to claim 1, wherein the
average particle size is from 1 to 300 .mu.m.
4. A laminate having a primer layer being a heat-treated product of
the powder primer composition as defined in claim 1 and a top
coating layer made of a fluororesin, laminated in this order on the
surface of a substrate.
5. The laminate according to claim 4, wherein the peel strength of
the top coating layer to the substrate is at least 20 N/cm.
Description
TECHNICAL FIELD
[0001] The present invention relates to a powder primer composition
and a laminate using it.
BACKGROUND ART
[0002] An ethylene/tetrafluoroethylene copolymer (hereinafter
referred to also as "ETFE") is excellent in heat resistance,
chemical resistance, weather resistance, gas barrier properties,
etc. and is used in various fields including semiconductor
industry, automobile industry, chemical industry, etc. Pelletized
ETFE particles may be processed into various molded products by
extrusion molding, injection molding, etc. Further, finer ETFE
particles may be processed for coating or lining on the surface of
a heat-resistant substrate by a powder coating method such as an
electrostatic coating method, or a method such as a rotational
molding method, and thus utilized for improvement in chemical
resistance or protection of a metal surface of e.g. containers,
tanks, pipings, joints, etc. Especially, coating by an
electrostatic coating method is widely used, since it is thereby
possible to easily form a coating film on the surface of an
abnormally shaped article.
[0003] In general, as compared with a perfluorinated fluororesin
such as a polytetrafluoroethylene resin, ETFE has good adhesion
properties to a substrate, and therefore, in many cases, it is
applied directly on a substrate surface after applying surface
roughening treatment such as sand blasting to the substrate
surface. However, in recent years, an ETFE-coated article has been
required to be used in a severer environment, and it is desired to
improve the adhesion properties between ETFE and the substrate.
[0004] Under these circumstances, a powder primer composition
employing a reactive ETFE having reactive groups in ETFE molecules,
is known (e.g. Patent Document 1). Further, a liquid primer
composition employing a silane coupling agent in order to improve
the adhesion properties between ETFE and a substrate, is known
(e.g. Patent Document 2). Still further, an attempt to mix an epoxy
resin powder to a fluororesin powder, followed by heat-treatment at
from 180 to 200.degree. C., is known (e.g. Patent Document 3).
PRIOR ART DOCUMENTS
Patent Documents
[0005] Patent Document 1: JP-A-2006-206637
[0006] Patent Document 2: JP-A-2006-167689
[0007] Patent Document 3: U.S. Pat. No. 3,111,426
DISCLOSURE OF INVENTION
Technical Problem
[0008] However, still higher adhesion properties than the reactive
ETFE disclosed in Patent Document 1, are now desired between the
ETFE coating film and the substrate. Likewise, still higher
adhesion properties than the primer disclosed in Patent Document 2,
are now desired between the ETFE coating film and the substrate.
Further, in Patent Document 3, it is required to add at least 30%
of an epoxy resin in order to obtain sufficient adhesion
properties, whereby flowability of the powder tends to decrease,
and the thickness of the coating film tends to be uneven. Further,
usually the firing temperature for ETFE is high at a level of about
300.degree. C., whereby there are problems such that foaming or
swelling is likely to occur due to heat decomposition of the curing
agent or the epoxy resin in the firing step.
[0009] It is an object of the present invention to solve such
problems of the prior art as described above and to provide a
powder primer composition excellent in adhesion properties to a
substrate and a laminate obtained by using it.
Solution to Problem
[0010] The present invention provides a powder primer composition
comprising a powder made of a reactive ethylene/tetrafluoroethylene
copolymer containing repeating units (A) based on
tetrafluoroethylene, repeating units (B) based on ethylene, and
repeating units (C) based on a monomer having an acid anhydride
residue and a polymerizable unsaturated bond, wherein (C)/((A)+(B))
is from 1/10,000 to 5/100 by molar ratio; and a powder made of an
epoxy resin having an epoxy equivalent of from 500 to 2,700 and a
softening point of at least 70.degree. C.; wherein the mass ratio
of the powder made of a reactive ethylene/tetrafluoroethylene
copolymer to the powder made of an epoxy resin is from 99/1 to
80/20.
[0011] The present invention provides a laminate having a primer
layer being a heat-treated product of the powder primer composition
as defined above and a top coating layer made of a fluororesin,
laminated in this order on the surface of a substrate.
Advantageous Effects of Invention
[0012] By the present invention, it is possible to provide a powder
primer composition excellent in adhesion properties to a substrate
and a laminate obtained by using it.
DESCRIPTION OF EMBODIMENTS
[0013] In this specification, the term "step" is meant to include
not only an independent step but also a step which cannot be
definitely distinguished from another step, so long as the desired
object of that step is thereby accomplished. Further, a numerical
range represented by using "to" represents a range including the
numerical values given before and after "to" as the minimum value
and the maximum value, respectively. Further, the content of each
component in a composition means, when a plurality of materials
corresponding to each component are present in the composition, the
total amount of the plurality of materials present in the
composition, unless otherwise specified.
Powder Primer Composition
[0014] A primer layer to be formed from the powder primer
composition of the present invention (hereinafter also referred to
simply as "the primer composition") is excellent in adhesion
properties to a substrate, and especially is excellent in adhesion
properties to a substrate and in adhesion properties to a top
coating layer made of a fluororesin to be formed on the primer
layer. Further, the primer composition is excellent in storage
stability. Furthermore, it is excellent in coating properties, and
it is thereby possible to readily obtain a coating layer with high
uniformity.
[0015] The average particle size of the primer composition is not
particularly limited, and may be from 1 to 1,000 .mu.m, preferably
from 1 to 300 .mu.m, more preferably from 3 to 300 .mu.m,
particularly preferably from 5 to 200 .mu.m. When the average
particle size is at least 1 .mu.m, the deposition amount at the
time of coating increases, whereby the adhesion force and
durability will be stabilized, and when it is at most 1,000 .mu.m,
dropout of particles after coating tends to be less, and the
surface smoothness tends to be good. The average particle size of
the primer composition is meant for the average particle size of
the entire powder contained in the composition. The average
particle size of the primer composition is a median size on
volumetric basis as measured by means of a laser diffraction
scattering particle size distribution measuring apparatus.
[0016] The bulk density of the primer composition is not
particularly limited, but is preferably from 0.4 to 1.2 g/cc, more
preferably from 0.5 to 1.0 g/cc. When the bulk density is at least
0.4 g/cc, the deposition amount at the time of coating increases,
whereby the adhesion force and durability will be stabilized, and
it is possible to prevent defects in the coating film due to air
bubbles to be formed during the firing. And, when it is at most 1.2
g/cc, dropout of particles at the time of coating tends to be less,
and the surface smoothness tends to be good. The bulk density can
be measured by the method disclosed in JIS K6891.
[0017] The angle of repose of the primer composition is not
particularly limited, but is preferably from 20 to 52 degrees, more
preferably from 30 to 50 degrees. When the angle of repose is at
least 20 degrees, the production is not difficult, and when it is
at most 52 degrees, the powder flowability tends to be improved,
and it tends to be possible to prevent such a problem as clogging
of a coating gun or formation of bridges in the powder supply tank
during the electrostatic coating. The angle of repose can easily be
obtained by reading the angle of repose of a powder dropped on a
repose angle measuring device by a protractor, and it is possible
to use e.g. a repose angle measuring device manufactured by AS ONE
Corporation, or Powder Tester PTX model manufactured by Hosokawa
Micron Ltd.
Powder Made of Reactive Ethylene/Tetrafluoroethylene Copolymer
[0018] The powder made of a reactive ethylene/tetrafluoroethylene
copolymer (hereinafter referred to also as "reactive ETFE powder")
contains repeating units (A) based on tetrafluoroethylene
(hereinafter referred to also as "TFE") (hereinafter referred to
also as "repeating units (A)"), repeating units (B) based on
ethylene (hereinafter referred to also as "repeating units (B)"),
and repeating units (C) based on a monomer having an acid anhydride
residue and a polymerizable unsaturated bond (hereinafter referred
to also as "repeating units (C)").
[0019] In the present invention, the reactive ETFE powder will
react with an epoxy resin in a firing step at a temperature of from
200 to 320.degree. C., but its reaction at room temperature is
extremely suppressed, whereby it can be stably stored for a long
period of time.
[0020] As the reactive ETFE powder, one type may be used alone, or
two or more types may be used in combination.
Repeating Units (C) Based on a Monomer Having an Acid Anhydride
Residue and a Polymerizable Unsaturated Bond
[0021] The reactive ETFE powder contains at least one type of
repeating units (C). The repeating units (C) are formed by
polymerization of a monomer having an acid anhydride residue and a
polymerizable unsaturated bond by itself or with
tetrafluoroethylene or ethylene. The repeating units (C) may have
an acid anhydride group derived from the monomer, as it is, or may
have an acidic functional group formed by hydrolysis of the acid
anhydride group. The repeating units (C) may be one type alone, or
a combination of two or more types.
[0022] The monomer having an acid anhydride residue and a
polymerizable unsaturated bond, to constitute the repeating units
(C), is not particularly limited, and may, for example, be maleic
anhydride, itaconic anhydride (hereinafter referred to as "IAH"),
citraconic anhydride (hereinafter referred to as "CAH"), or
5-norbornene-2,3-dicarboxylic anhydride. Preferred is IAH or CAH.
When IAH or CAH is used, reactive ETFE tends to be easily
obtainable.
[0023] As the monomer having an acid anhydride residue and a
polymerizable unsaturated bond, one type may be used alone, or two
or more types may be used in combination.
[0024] In the present invention, the content ratio of (C)/((A)+(B))
is from 1/10,000 to 5/100 by molar ratio. If (C)/((A)+(B)) is less
than 1/10,000, the chemical reaction with the powder made of an
epoxy resin tends to be too little in the firing step to produce a
primer layer, whereby it tends to be difficult to obtain a high
adhesion force to a substrate. On the other hand, if (C)/((A)+(B))
exceeds 5/100, the chemical resistance or the heat resistance tends
to be low. (C)/((A)+(B)) is preferably from 1/1,000 to 5/100, more
preferably from 3/2,000 to 3/100, particularly preferably from
3/1,000 to 3/100. Within such a range, the adhesion properties tend
to be further excellent, and the chemical resistance or heat
resistance tends to be further excellent.
[0025] In the present invention, the content ratio of (A) to (B) is
not particularly limited, but (A)/(B) is preferably from 20/80 to
80/20, more preferably from 50/50 to 70/30, by molar ratio. When
(A)/(B) is at least 20/80, the heat resistance, weather resistance,
chemical resistance and gas barrier property tend to be further
improved, and when (A)/(B) is at most 80/20, the mechanical
strength and melting properties tend to be further improved.
[0026] In the present invention, the contents of repeating units
(A), (B) and (C) correspond substantially to the charged amounts of
monomers to constitute the respective repeating units.
Repeating Units (D) Based on Other Monomers
[0027] The reactive ETFE in the present invention may contain, in
addition to repeating units (A), (B) and (C), repeating units (D)
based on other monomers other than monomers to constitute repeating
units (A), (B) and (C) (hereinafter referred to also as "repeating
units (D)"). Repeating units (D) may be one type alone, or a
combination of two or more types.
[0028] Other monomers to constitute the repeating units (D) may,
for example, be a hydrocarbon-type olefin having at least three
carbon atoms, such as propylene or butene; a compound represented
by CH.sub.2.dbd.CX(CF.sub.2).sub.nY (wherein X and Y are each
independently a hydrogen atom or a fluorine atom, and n is an
integer of from 2 to 8); a fluoro-olefin having hydrogen atoms in
an unsaturated group, such as vinylidene fluoride, vinyl fluoride
or trifluoroethylene; a fluoro-olefin having no hydrogen atom in an
unsaturated group (excluding TFE), such as hexafluoropropylene or
chlorotrifluoroethylene; a perfluoro(alkyl vinyl ether) such as
perfluoro(propyl vinyl ether); a vinyl ether, such as an alkyl
vinyl ether, a (fluoroalkyl) vinyl ether, glycidyl vinyl ether,
hydroxybutyl vinyl ether or methyl vinyloxybutyl carbonate; an
vinyl ester such as vinyl acetate, vinyl chloroacetate, vinyl
butanoate, vinyl pivalate, vinyl benzoate or vinyl crotonate; a
(meth)acrylate such as a (polyfluoroalkyl) acrylate or a
(polyfluoroalkyl) methacrylate; etc.
[0029] As such other monomers, one type may be used alone, or two
or more types may be used in combination.
[0030] As such other monomers, at least one member selected from
the group consisting of hexafluoropropylene, perfluoro(propyl vinyl
ether) and a compound represented by the above
CH.sub.2.dbd.CX(CF.sub.2).sub.nY, is preferred. Among them, a
compound represented by the above CH.sub.2.dbd.CX(CF.sub.2).sub.nY
is more preferred, and one wherein n=2 to 4, is particularly
preferred. Specific examples of the compound represented by
CH.sub.2.dbd.CF(CF.sub.2).sub.2F, CH.sub.2.dbd.CF(CF.sub.2).sub.3F,
CH.sub.2.dbd.CF(CF.sub.2).sub.4F, CH.sub.2.dbd.CF(CF.sub.2).sub.2H,
CH.sub.2.dbd.CF(CF.sub.2).sub.3H, CH.sub.2.dbd.CF(CF.sub.2).sub.4H,
CH.sub.2.dbd.CH(CF.sub.2).sub.2F, CH.sub.2.dbd.CH(CF.sub.2).sub.3F,
CH.sub.2.dbd.CH(CF.sub.2).sub.4F, CH.sub.2.dbd.CH(CF.sub.2).sub.2H,
CH.sub.2.dbd.CH(CF.sub.2).sub.3H, CH.sub.2.dbd.CH(CF.sub.2).sub.4H,
etc. CH.sub.2.dbd.CF(CF.sub.2).sub.2F,
CH.sub.2.dbd.CH(CF.sub.2).sub.2F, CH.sub.2.dbd.CH(CF.sub.2).sub.2H
or CH.sub.2.dbd.CF(CF.sub.2).sub.2H is preferred, and
CH.sub.2.dbd.CH(CF.sub.2).sub.2F is more preferred.
[0031] The content of repeating units (D) is preferably from 0 to
20 mol %, more preferably from 0 to 15 mol %, particularly
preferably from 0 to 10 mol %, to all repeating units in the
reactive ethylene/tetrafluoroethylene copolymer. In the present
invention, the content of repeating units (D) corresponds
substantially to the charged amount of other monomers.
Average Particle Size
[0032] The average particle size of the reactive ETFE powder is not
particularly limited, and may be from 1 to 1,000 .mu.m, preferably
from 1 to 300 .mu.m, more preferably from 3 to 300 .mu.m,
particularly preferably from 5 to 200 .mu.m. When the average
particle size is at least 1 .mu.m, the deposition amount of the
reactive ETFE powder at the time of coating increases, whereby the
number of repeated coating times may be made less, and when it is
at most 1,000 .mu.m, dropout of the reactive ETFE powder after the
coating tends to be less, and the surface smoothness tends to be
excellent. The average particle size of the reactive ETFE powder is
a median size on volumetric basis as measured by means of a laser
diffraction scattering particle size distribution apparatus.
Preparation Method
[0033] The method for producing the reactive ETFE powder is not
particularly limited, but a method may be mentioned wherein
reactive ETFE is produced, followed by pulverization treatment. The
method for producing reactive ETFE is not particularly limited, but
a method disclosed in JP-A-2004-238405 may, for example, be
mentioned. Here, in a case where a dispersion of reactive ETFE is
produced, the ETFE dispersion may be directly sprayed to vaporize
and remove the medium to obtain reactive ETFE powder. The
pulverization treatment may, for example, be a method wherein
reactive ETFE powder contained in the ETFE dispersion is granulated
to an intermediate particle size, followed by drying, and then,
pulverized by a pulverizer such as a hammer mill, a turbo mill, a
cutting mill, a crusher, a jet mill or a counter jet mill, or a
method of mechanically pulverizing reactive ETFE at a low
temperature of less than room temperature where reactive ETFE is
embrittled (hereinafter referred to also as "freeze-crushing"). By
freeze-crushing, reactive ETFE powder with a small particle size
can easily be obtained.
[0034] In the case of freeze-crushing, pulverization is carried out
while cooling with a cooling medium such as liquefied carbon
dioxide gas or liquid nitrogen. As the freeze-crushing apparatus, a
freeze-crushing machine manufactured by AS ONE Corporation, or
Linrex Mill manufactured by Hosokawa Micron Corporation may, for
example, be used. The temperature at the time of pulverization is
preferably from -200 to 20.degree. C., more preferably from -180 to
-20.degree. C., particularly preferably from -150 to -50.degree. C.
Here, the particle size of the reactive ETFE powder may be adjusted
by classifying by means of sieves or an air stream
Powder Made of Epoxy Resin
[0035] The powder made of an epoxy resin is solid at normal
temperature (e.g. 25.degree. C.). The epoxy resin is meant for a
resin having at least one epoxy group in one molecule. The epoxy
resin is not particularly limited, and may, for example, be a
bisphenol A-type epoxy resin obtainable by a condensation reaction
of bisphenol A with epichlorohydrin, a bisphenol F-type epoxy
resin, a bisphenol AD-type epoxy resin, a phenol novolac-type epoxy
resin, a cresol novolac-type epoxy resin, a glycidyl ester-type
epoxy resin, a biphenyl-type epoxy resin, a polymer-type epoxy
resin, other modified epoxy resins, etc.
[0036] As the powder made of an epoxy resin, one type may be used
alone, or two or more types may be used in combination.
[0037] The powder made of an epoxy resin has a softening point of
at least 70.degree. C. If the softening point of the powder made of
an epoxy resin is lower than 70.degree. C., the storage stability
of the primer composition tends to be low, and foaming or change in
color tends to be likely to occur. The softening point of the epoxy
resin is preferably from 80 to 140.degree. C., more preferably from
90 to 130.degree. C. When the softening point of the powder made of
an epoxy resin is at most 140.degree. C., melting tends to be easy
at the time of heat treatment, and the adhesion force tends to be
improved. Here, the softening point of the epoxy resin can be
measured by the method disclosed in JIS K7234 (ring-and-ball
method).
[0038] The molecular weight of the epoxy resin is not particularly
limited, but is preferably from 1,000 to 3,500, more preferably
from 1,500 to 3,000. When the molecular weight of the epoxy resin
is at least 1,000, a cross-linking reaction tends to be less likely
to take place during the storage, the storage stability tends to be
improved, and foaming or change in color tends to be suppressed,
and when it is at most 3,500, melting tends to be easy at the time
of heat treatment, and the adhesion force tends to be improved.
[0039] The epoxy equivalent of the powder made of an epoxy resin is
from 500 to 2,700, preferably from 700 to 2,300, more preferably
from 900 to 2,000. If the epoxy equivalent is less than 500, the
storage stability tends to be low, and foaming or change in color
tends to be likely to occur, and if it exceeds 2,700, melting tends
to be difficult at the time of heat treatment, and the adhesion
force tends to be low. The epoxy equivalent is the number of grams
of a resin containing one gram equivalent of epoxy groups, and can
be measured by the method disclosed in JIS K7236 (potentiometric
titration).
[0040] As such an epoxy resin, as a solid epoxy resin as a
commercial product, epoxy resin jER (registered trademark) 1004,
1004K, 1004F, 1004AF or 1007 manufactured by Mitsubishi Chemical
Corporation, or epoxy resin Epiclon (registered trademark) 4050 or
7050 manufactured by DIC Corporation, may, for example, be
mentioned.
Average Particle Size
[0041] The average particle size of the powder made of an epoxy
resin is not particularly limited, and may be from 1 to 1,000
.mu.m, preferably from 1 to 300 .mu.m, more preferably from 3 to
200 .mu.m, particularly preferably from 5 to 50 .mu.m. When the
average particle size of the powder made of an epoxy resin is at
least 1 .mu.m, the storage stability tends to be improved, and the
powder flowability tends to be improved, and when it is at most
1,000 .mu.m, the reactivity with the reactive ETFE powder at the
time of heat treatment tends to be improved, and the adhesion force
tends to be improved. The average particle size of the powder made
of an epoxy resin is a median size on volumetric basis as measured
by means of a laser diffraction scattering particle size
distribution apparatus.
Preparation Method
[0042] The method for producing the powder made of an epoxy resin
is not particularly limited, and a method of pulverizing the
above-mentioned commercially available solid epoxy resin may be
mentioned. The pulverization method may, for example, be a method
of pulverizing by means of a pulverizer such as a hammer mill, a
turbo mill, a cutting mill, a crusher, a jet mill or a counter jet
mill, or a method of freeze-crushing it at a low temperature. Here,
in a case where the average particle size of the above-mentioned
commercially available solid epoxy resin is within the
above-mentioned preferred range of the particle size of the powder
made of an epoxy resin, such a resin may be used as it is.
[0043] Further, the particle size of the powder made of an epoxy
resin may be adjusted by classifying by means of sieves or an air
stream.
[0044] In the primer composition, the mass ratio of the reactive
ETFE powder to the powder made of an epoxy resin is from 99/1 to
80/20, preferably from 98/2 to 85/15, particularly preferably from
97/3 to 88/12. If the mass ratio of the reactive ETFE powder to the
powder made of an epoxy resin exceeds 99/1, the adhesion force
tends to be low, and if the mass ratio of the reactive ETFE powder
to the powder made of an epoxy resin is less than 80/20, the
flowability of the primer composition tends to be low, whereby
coating tends to be non-uniform, and foaming or color change tends
to be likely to occur due to heat decomposition of the epoxy
resin.
Further Components
[0045] The primer composition may contain further components within
a range to obtain the effects of the present invention. The primer
composition may contain, as a coloring agent, a pigment such as
carbon black, graphite, cobalt blue, ultramarine or titanium oxide;
silica, alumina, etc. to improve the flowability; an inorganic
filler as a reinforcing material; other synthetic resin powders;
etc. The content of these components may be at most 5.0 parts by
mass, preferably from 0.1 to 5.0 parts by mass, particularly
preferably from 0.1 to 3.0 parts by mass.
[0046] Further, the primer composition may contain a thermal
stabilizer such as a copper compound, a tin compound, an iron
compound, a lead compound, a titanium compound or an aluminum
compound, within a range not to impair the adhesion effects of the
primer composition. The content of the thermal stabilizer may be
less than 1.0 part by mass, preferably less than 0.1 part by mass,
per 100 parts by mass in total of the reactive ETFE powder and the
powder made of an epoxy resin, more preferably not substantially
contained.
Preparation Method
[0047] The primer composition can be produced by mixing the
respective components. The mixing method may, for example, be a dry
blending method by means of e.g. a V type blender, a double cone
type blender, a container blender, a drum type blender, a
horizontal cylinder type mixer, a ribbon mixer, a paddle mixer or a
screw mixer. Here, the mixing is preferably conducted at a
temperature of less than the softening point of the powder made of
an epoxy resin. For example, if mixed for a long time in a mixing
device with a strong shear force or centrifugal force such as a
Henschel mixer, the epoxy resin will be softened and fixed to the
reactive ETFE powder to form nodules, whereby the powder
flowability tends to be lowered. Further, during the mixing, a
chemical reaction is likely to take place between the reactive ETFE
powder and the powder made of an epoxy resin, such being
undesirable.
Laminate
[0048] In the present invention, the laminate is one having a
primer layer being a heat-treated product of the primer composition
and a top coating layer made of a fluoro-resin, laminated in this
order on the surface of a substrate. The laminate may further be
such that on the surface of the top coating layer, a coating layer
of an organic or inorganic material being a material different from
the top coating layer, may be laminated.
[0049] The laminate is excellent in heat resistance, durability
such as alkali resistance and adhesion properties.
Substrate
[0050] The substrate in the present invention is not particularly
limited and may, for example, be a metal such as iron, stainless
steel, aluminum, copper, tin, titanium, chromium, nickel or zinc,
glass, or heat-resistant material such as ceramic. Among them,
iron, stainless steel or aluminum is preferred.
[0051] The shape of the substrate in the present invention is not
particularly limited and may, for example, be a pipe, a tube, a
film, a plate, a tank, a roll, a vessel, a bulb or an elbow, and it
may be used for, for example, various containers, pipes, tubes,
tanks, pipe lines, joints, rolls, autoclaves, heat exchangers,
distillation towers, jigs, bulbs, stirring vanes, tanker lorries,
pumps, casings for blowers, centrifugal separators, kitchen
utensils, etc.
Primer Layer
[0052] The primer layer in the present invention is a heat-treated
product of the primer composition. The primer composition is as
described above including its preferred embodiments. The thickness
of the primer layer is preferably from 1 to 1,000 .mu.m, more
preferably from 5 to 500 .mu.m, most preferably from 10 to 200
.mu.m. When the thickness of the primer layer is at least 1 .mu.m,
the adhesion properties will be sufficiently exhibited, and when it
is at most 1,000 .mu.m, foaming or swelling tends to be less likely
to occur.
Top Coating Layer
[0053] The top coating layer made of a fluoro-resin can be formed
by applying a powder made of a fluoro-resin or a powdery top
coating composition containing a powder made of a fluoro-resin,
followed by curing.
Powder Made of Fluoro-Resin or Powdery Top Coating Composition
Containing Powder Made of Fluoro-Resin
[0054] The powder made of a fluoro-resin is a powder of a
fluoro-resin which is solid at normal temperature (e.g. 25.degree.
C.). The fluoro-resin is not particularly limited, and may, for
example, be a homopolymer or copolymer of a fluorinated monomer,
provided that the above-described reactive ETFE is excluded. The
fluorinated monomer may, for example, be the above-mentioned, TFE,
fluoro-olefin having hydrogen atoms in an unsaturated bond,
fluoro-olefin having no hydrogen atom in an unsaturated bond
(excluding TFE) or perfluoroalkyl vinyl ether. Further, the
fluoro-resin may be a copolymer wherein the above-mentioned,
ethylene, hydrocarbon-type olefin having at least 3 carbon atoms,
monomer having an acid anhydride residue and a polymerizable
unsaturated bond, vinyl ether, vinyl ester, or a monomer having no
fluorine atom, such as a (meth)acrylate, is used as a co-monomer
component.
[0055] As such a fluoro-resin, a non-reactive
ethylene/tetrafluoroethylene copolymer (hereinafter referred to
also as "non-reactive ETFE"), a propylene/TFE copolymer, a
TFE/perfluoro(alkyl vinyl ether) copolymer, a
TFE/hexafluoropropylene copolymer, a
TFE/hexafluoropropylene/vinylidene fluoride copolymer, a
chlorotrifluoroethylene/ethylene copolymer, a vinylidene fluoride
copolymer or a hexafluoropropylene/vinylidene fluoride may, for
example, be mentioned, and a non-reactive ETFE is preferred. That
is, in the present invention, the top coating layer made of a
fluoro-resin is preferably one obtainable by using a powder made of
a non-reactive ETFE (hereinafter referred to also as "non-reactive
ETFE powder") or a powdery top coating composition containing a
powder made of a non-reactive ETFE.
[0056] The non-reactive ETFE powder means an ETFE powder wherein
(C)/((A)+(B)) in the above definition of the reactive ETFE powder
is less than 1/10,000 by molar ratio. Further, the non-reactive
ETFE powder may contain repeating units (D) based on other
monomers. Except that (C)/((A)+(B)) is less than 1/10,000 by molar
ratio, the non-reactive ETFE powder is as described above with
respect to the reactive ETFE powder including its preferred
embodiments. As specific examples of the non-reactive ETFE powder,
Fluon (registered trademark) TL-081, Z-8820X and LM-2150 (each has
no repeating units (C) based on a monomer having an acid anhydride
residue and a polymerizable unsaturated bond), manufactured by
Asahi Glass Co., Ltd., may be mentioned.
[0057] As the powder made of a fluoro-resin, one type may be used
alone, or two or more types may be used in combination.
[0058] The average particle size of the powder made of a
fluoro-resin is preferably from 1 to 1,000 .mu.m, more preferably
from 5 to 300 .mu.m, particularly preferably from 10 to 200 .mu.m.
When the average particle size of the powder made of a fluoro-resin
is at least 1 .mu.m, the deposition amount is less likely to be too
small, and the number of coating times to attain a prescribed
thickness may be reduced, and when it is at most 1,000 .mu.m,
smoothness of the surface tends to be maintained. The average
particle size of the powder made of a fluoro-resin is a median size
on volumetric basis as measured by means of a laser diffraction
scattering particle size distribution apparatus.
[0059] Further, the powdery top coating composition containing the
powder made of a fluoro-resin preferably contains a thermal
stabilizer such as a copper compound, a tin compound, an iron
compound, a lead compound, a titanium compound or an aluminum
compound. When it contains a thermal stabilizer, yellowing or
sagging due to thermal degradation in the firing step tends to be
less likely to occur. The content of the thermal stabilizer is
preferably from 1.times.10.sup.-8 to 5 mass %, more preferably from
1.times.10.sup.-7 to 1 mass %, particularly preferably from
5.times.10.sup.-7 to 0.1 mass %, in the top coating composition.
Further, the specific surface area of the thermal stabilizer is
preferably from 0.1 to 100 m.sup.2/g, more preferably from 1 to 70
m.sup.2/g, particularly preferably from 5 to 50 m.sup.2/g. The
specific surface area is one measured by a BET method.
Thickness of Top Coating Layer
[0060] As the thickness of the top coating layer, an optimum
thickness may be selected within a range of from 10 to 5,000 .mu.m.
For the purpose of e.g. improving water repellency, improving an
antifouling property or improving glossiness, of the substrate
surface, a thickness of from 10 to 100 .mu.m is preferred; for the
purpose of improving lubricity of the substrate surface or
protection of the surface, a thickness of from 50 to 500 .mu.m is
preferred; for the purpose of protection of the substrate against
an organic reagent or an inorganic reagent, a thickness of from 200
to 1,000 .mu.m is preferred; and particularly in a case where
durability for a very long period of time is required, a thickness
of from 1,000 to 5,000 .mu.m is preferred. If too thin, the
covering effects tend to be insufficient, and if too thick, the
number of coating times is required to be increased, such being not
only economically disadvantageous, but also stress-strain is likely
to occur due to a difference in the thermal expansion coefficient
from the substrate, such being undesirable.
Coating Layer of Organic or Inorganic Material as a Material
Different From Top Coating Layer
[0061] A coating layer of an organic or inorganic material as a
material different from the top coating layer (hereinafter referred
to also as a "further coating layer") may, for example, be a
coloring layer, a hard coating layer or a penetration-preventing
layer. When the laminate further contains such a coating layer, it
will have a further effect such as a coloring effect, a hard
coating effect or a penetration-preventing effect. The thickness of
the further coating layer is not particularly limited, and may be
from 0 to 1,000 .mu.m, preferably from 0 to 500 .mu.m. The
thickness of the further coating layer may be adjusted depending
upon the characteristics to be imparted by the further coating
layer.
Peel Strength
[0062] In the laminate of the present invention, the adhesion force
of the top coating layer to the substrate can be ascertained by
measuring the 90.degree. peel strength. The higher the adhesion
force, the better. However, it is preferably a peel strength of at
least 20 N/cm, more preferably a peel strength of at least 40 N/cm,
particularly preferably a peel strength of at least 50 N/cm. If the
peel strength is less than 20 N/cm, the adhesion reliability is
low, and depending upon the application environment, peeling or
blistering of the coating film or corrosion deterioration of the
substrate is likely to be brought about, such being
undesirable.
Process for Producing Laminate
[0063] In the present invention, the laminate is obtainable by a
production process comprising a step of forming a primer layer on a
substrate surface, and a step of forming a top coating layer on the
surface of the primer layer, and, as the case requires, containing
a step of forming a further coating layer on the surface of the top
coating layer.
Process for Producing Primer Layer
[0064] The primer layer is obtainable by a production process
comprising a step of applying the primer composition of the present
invention to the surface of a substrate to form a primer
composition layer, and a step of heat-treating the primer
composition layer to form a primer layer. By the heat treatment,
the reactive ETFE powder and the powder made of an epoxy resin are
chemically reacted and cured to form a primer layer.
[0065] The method for applying the primer composition is not
particularly limited, and a known powder coating method, such as an
electrostatic coating method, a fluidized dipping method or a
rotational molding method, may be mentioned. Among them, an
electrostatic coating method is preferred, since it is simple, and
a large area can thereby be coated with a uniform thickness. As the
coating machine, various commercially available electrostatic
coating devices may be used, and by applying static electricity at
a voltage of from -100 to -30 kV, the primer composition may be
sprayed together with an air stream.
[0066] The thickness of the primer composition layer to be applied
on the substrate is such a thickness that it would become the
thickness of the above-mentioned primer layer, including preferred
ones. Here, when the thickness of the primer composition is within
the above range, sufficient adhesion properties will be developed
by applying the primer composition once, however, the primer
composition may be applied plural times. Further, the thickness of
the primer composition may be adjusted depending upon the thickness
of the primer layer after the heat treatment.
[0067] The amount of the primer composition to be applied on the
substrate is not particularly limited, so long as it is an amount
to obtain the above mentioned thickness of the primer composition,
and it is preferably from 1.6 to 1,600 g/m.sup.2, more preferably
from 8.0 to 800 g/m.sup.2.
[0068] The heat treatment of the primer composition layer can be
carried out by an optional heating means, such as an electric
furnace, gas furnace or infrared heating furnace, set at a
predetermined temperature.
[0069] The heat treatment temperature is preferably from 260 to
340.degree. C., more preferably from 280 to 320.degree. C.,
particularly preferably from 290 to 310.degree. C. When the heat
treatment temperature is at least 260.degree. C., lowering of the
adhesion force or remaining of voids or air bubbles due to firing
deficiency, tends to be less likely to occur, and when it is at
most 340.degree. C., change in color or formation of foams tends to
be suppressed. The heat treatment time may vary depending upon the
heat treatment temperature, but heat treatment within a range of
from 1 to 180 minutes is preferred, and more preferred is from 5 to
120 minutes, and particularly preferred is from 10 to 60 minutes.
When the heat treatment time is at least 1 minute, lowering of the
adhesion force or remaining of air bubbles due to firing deficiency
tends to be less likely to occur, and when it is at most 180
minutes, change in color or formation of foams tends to be
suppressed.
[0070] Prior to application of the primer composition, the
substrate may be preheated at a temperature of at most 200.degree.
C. Further, prior to application of the primer composition, the
substrate surface may be surface-roughened by e.g. sand blast
treatment, etching treatment or metal spray treatment, or cleaning
with a solvent may be carried out to remove foreign matters
deposited on the surface. Thereby, the adhesion properties tend to
be improved. Here, in the case of sand blast treatment, the surface
roughness Ra can be adjusted within a range of from 1 to 100 .mu.m
depending upon the adhesion properties or use.
Process for Producing Top Coating Layer
[0071] The top coating layer is obtainable by a production process
comprising a step of applying a powder made of a fluoro-resin, or a
top coating composition containing a powder made of a fluoro-resin,
on the surface of the primer layer laminated on a substrate
surface, to form a powder layer made of a fluoro-resin or a top
coating composition layer containing the powder made of a
fluoro-resin, and a step of heat-treating the powder layer made of
a fluoro-resin or the top coating composition layer containing the
powder made of a fluoro-resin, to form a top coating layer.
[0072] The method for applying the powder made of a fluoro-resin or
the top coating composition containing the powder made of a
fluoro-resin, is not particularly limited, and a method of applying
the primer coating composition may be mentioned, and a known powder
coating method such as an electrostatic coating method, a fluidized
dipping method or a rotational molding method, may be applied, but
an electrostatic coating method is preferred, since the application
can thereby be made simply in a uniform thickness.
[0073] The thickness of the powder layer made of a fluoro-resin or
the top coating composition layer containing the powder made of a
fluoro-resin, to be formed on the surface to the primer layer, is
such a thickness that it would become the thickness of the
above-mentioned top coating layer, including preferred ones. Here,
when the thickness of the powder layer made of a fluoro-resin or
the top coating composition layer containing the powder made of a
fluoro-resin is within the above range, it is sufficient to apply
the powder made of a fluoro-resin or the top coating composition
containing the powder made of a fluoro-resin once, however, the
powder made of a fluoro-resin or the top coating composition
containing the powder made of a fluoro-resin may be applied plural
times. Further, the thickness of the powder layer made of a
fluoro-resin or the top coating composition layer containing the
powder made of a fluoro-resin may be adjusted depending upon the
thickness after the firing. In a case where the top coating layer
is formed plural times, such a plurality of top coating layers may
be collectively referred to as the top coating layer.
[0074] The amount of the powder made of a fluoro-resin or the top
coating composition containing the powder made of a fluoro-resin,
to be applied on the surface of the primer layer, is not
particularly limited, so long as it is an amount to become the
above-mentioned thickness of the top coating layer.
[0075] The heat treatment of the powder layer made of a
fluoro-resin or the top coating composition layer containing the
powder made of a fluoro-resin, is not particularly limited, so long
as it is under such a condition that the top coating layer is
formed on the surface of the primer layer, and it may be conducted
by an optional means, such as an electric furnace, a gas furnace or
an infrared heating furnace, set at a predetermined temperature.
The heat treatment temperature is preferably from 260 to
340.degree. C., more preferably from 280 to 320.degree. C.,
particularly preferably from 290 to 310.degree. C. When the heat
treatment temperature is at least 260.degree. C., remaining of
voids or air bubbles due to firing deficiency tends to be less
likely to occur, and when it is at most 340.degree. C., change in
color or foaming tends to be less likely to occur.
[0076] The heat treatment time may vary depending upon the heat
treatment temperature, but heat treatment within a range of from 1
to 180 minutes is preferred, and more preferred is from 5 to 120
minutes, and particularly preferred is from 10 to 60 minutes. When
the heat treatment time is at least 1 minute, remaining of air
bubbles due to firing deficiency tends to be less likely to occur,
and when it is at most 180 minutes, change in color or sagging
tends to be less likely to occur.
Process for Producing Coating Layer of Organic or Inorganic
Material as a Material Different From Top Coating Layer
[0077] The further coating layer is obtainable by a production
process comprising a step of applying a composition for a coating
layer of an organic or inorganic material as a material different
from the top coating, on the surface of the top coating layer, and
a step of forming the further coating layer. The thickness of the
coating layer of an organic or inorganic material as a material
different from the top coating, is not particularly limited, and
may be the thickness of the above-mentioned further coating layer.
The composition for the further coating layer and the conditions
for the process for producing the further coating layer, are not
particularly limited, and conditions which are commonly used for
forming a further coating layer, may be mentioned.
EXAMPLES
[0078] Now, the present invention will be described in detail with
reference to Examples, but the present invention is by no means
limited thereto. Ex. 1 to 5 are Examples of the present invention,
and Ex. 6 to 11 are Comparative Examples. The coating and
evaluations in each Ex. were conducted by the following
methods.
Coating Thickness
[0079] Five points were measured by an electromagnetic film
thickness meter, and an average value was obtained.
Judgement of Appearance
[0080] A case where no abnormality is observed during the
application of the powder coating composition or on the coating
film appearance of a primer layer-attached substrate or a coating
test specimen, was rated as rank A, and a case where sagging or
thickness irregularities are observed, or abnormality such as air
bubbles or swelling, or irregularities in coating film thickness,
are confirmed, ranking was made by the following standards, and
rank D was taken as unacceptable.
[0081] Very uniform appearance: rank A
[0082] Generally uniform appearance: rank B
[0083] Slight abnormality observed: rank C
[0084] Substantial abnormality observed: rank D
Evaluation of Initial Adhesion Properties
[0085] On the surface of a coating test specimen or a primer
layer-attached substrate, by using a cutter knife, cuts were made
at 10 mm intervals, whereupon a part of the top coating layer was
peeled and then fixed to a chuck of a tensile tester, and the
90.degree. peel strength was measured at a tensile speed of 50
mm/min. With respect to the obtained initial peel strength, ranking
was made by the following standards, and rank D was taken as
unacceptable.
[0086] Peel strength.gtoreq.50.0 N/cm: rank A [0087] At least 40.0
and less than 50.0 N/cm: rank B [0088] At least 20.0 and less than
40.0 N/cm: rank C [0089] <20.0 N/cm: rank D
Hydrothermal Resistance
[0090] A coating test specimen was treated at 130.degree. C. for 24
hours by a pressure cooker (high temperature vapor pressure
vessel), whereupon in the same manner as the evaluation of the
initial adhesion properties, the peel strength of the top coating
layer was measured. With respect to the obtained peel strength
after the hydrothermal resistance test, ranking was made in the
same manner as the evaluation of the initial peel strength.
Alkali Resistance
[0091] A coating test specimen was immersed in a 10 mass % sodium
hydroxide aqueous solution at 80.degree. C. for 300 hours,
whereupon in the same manner as the evaluation of the initial
adhesion properties, the peel strength of the top coating layer was
measured. With respect to the obtained peel strength after the
alkali resistance test, ranking was made in the same manner as the
evaluation of the initial peel strength.
Average Particle Size
[0092] Each powder was dispersed in a 0.1 mass % surfactant (Newcol
1308FA(90), manufactured by Nippon Nyukazai Co., Ltd.) aqueous
solution, and the median average particle size on volumetric basis
was measured by means of a laser scattering particle size
distribution meter (LA-920, manufactured by Horiba, Ltd).
Bulk Density
[0093] Measured by the method disclosed in JIS K6891.
Angle of Repose
[0094] The angle of repose was measured by a repose angle meter (a
turn table type repose angle meter, manufactured by Tsutsui
Scientific Instruments Co., Ltd.). The smaller the angle of repose,
the better the powder flowability.
Storage Stability
[0095] A powder primer composition was stored at 40.degree. C. for
300 hours, whereupon ranking was made based on formation of nodules
and powder flowability.
[0096] No formation of nodules is observed, and the flowability is
good: rank A
[0097] No formation of nodules is observed, but the flowability is
slightly low: rank B
[0098] Nodules are formed, but easily disintegratable to be useful:
rank C
[0099] Nodules are formed to be hardly useful: rank D
Ex. 1
Production of Reactive ETFE Powder (Reactive ETFE-1)
[0100] ETFE comprising repeating units (A) based on TFE/repeating
units (B) based on ethylene/repeating units (C) based on
IAH/repeating units (D) based on CH.sub.2.dbd.CH(CF.sub.2).sub.4F
in a molar ratio of 57.6/40.0/1.8/0.6 (i.e. (C)/((A)+(B)) being
1.84/100 by molar ratio) and having a melting point of 242.degree.
C., was solution-polymerized and subjected to granulation
treatment, and the particles thereby obtained, were pulverized by a
freeze crusher TPH-01 manufactured by AS ONE Corporation, to obtain
reactive ETFE powder having an average particle size of 40 .mu.m
(reactive ETFE-1).
Production of Powder (EP-1) Made of Epoxy Resin
[0101] Powder (EP-1) made of an epoxy resin and having an average
particle size of 23 .mu.m, was obtained by pulverizing Epoxy Resin
1004 manufactured by Mitsubishi Chemical Corporation (epoxy
equivalent 925, molecular weight 1650, softening point 97.degree.
C.) by Freeze Crusher TPH-01, manufactured by AS ONE
Corporation.
Production of ETFE Powder Primer Composition (P-1)
[0102] The reactive ETFE powder (reactive ETFE-1) and powder (EP-1)
made of an epoxy resin were mixed in a mass ratio of 95/5 for one
minute by a V type blender to prepare ETFE powder primer
composition (P-1). The temperature after the mixing was 25.degree.
C., the powder flowability of the ETFE powder primer composition
after the mixing was good, and the average particle size was 39
.mu.m.
[0103] Further, with this ETFE powder primer composition, no
abnormality was observed after the storage stability test at
40.degree. C. for 300 hours.
Production of Laminate
[0104] The surface of a SUS 316 stainless steel plate having a
length of 50 mm, a breadth of 150 mm and a thickness of 2 mm was
subjected to sand blast treatment to bring the surface roughness
Ra=5 to 10 .mu.m by means of alumina particles of 60 mesh, and
then, the surface was cleaned with ethanol to prepare a substrate
for testing.
[0105] On the surface of this substrate for testing, the ETFE
powder primer composition (P-1) was sprayed by means of an
electrostatic coating gun for powder by an applied voltage of -60
kV, followed by firing at 300.degree. C. for 10 minutes as hanged
in an oven, to form a primer layer thereby to obtain a primer
layer-attached substrate.
[0106] Then, on its surface, as a non-reactive ETFE powder for top
coating, Fluon ETFE-TL-081 manufactured by Asahi Glass Co., Ltd.
(non-reactive ETFE-1, not containing repeating units (C) based on a
monomer having an acid anhydride residue and a polymerizable
unsaturated bond), was applied by electrostatic coating and fired
at 300.degree. C. for 10 minutes, and this electrostatic coating
and firing step was repeated three times, to form a top coating
layer having a total thickness of 370 .mu.m, thereby to obtain a
coating test specimen. The initial peel strength of the top coating
layer was 71.9 N/cm, and also after the hydrothermal resistance
test and the alkali resistance test, it showed a sufficient peel
strength.
Ex 2 and 3
[0107] ETFE powder primer composition (P-2) and ETFE powder primer
composition (P-3) were prepared by changing the blend amounts of
the reactive ETFE powder (reactive ETFE-1) and the powder (EP-1)
made of an epoxy resin, as shown in Table 1, and coating test
specimens were obtained. The same evaluation as in Ex. 1 was
conducted, whereby good results were obtained.
Ex. 4
[0108] Powder primer composition (P-4) was prepared with a blend
composition shown as Ex. 4 in Table 1, by using, as a powder made
of an epoxy resin, powder (EP-2) made of an epoxy resin with an
average particle size of 28 .mu.m, obtained by freeze-crushing
epoxy resin 1007 manufactured by Mitsubishi Chemical Corporation
(epoxy equivalent: 1,975, molecular weight: 2,900, softening point:
128.degree. C.). Further, by using, as a non-reactive ETFE powder
for top coating, Fluon ETFE-Z-8820X manufactured by Asahi Glass
Co., Ltd (non-reactive ETFE-2, not containing repeating units (C)
based on a monomer having an acid anhydride residue and a
polymerizable unsaturated bond), a coating test specimen was
obtained. The same evaluation as in Ex. 1 was conducted, whereby
good results were obtained.
Ex. 5
[0109] Reactive ETFE powder having an average particle size of 10
.mu.m (reactive ETFE-2) was obtained by changing the pulverization
conditions for ETFE powder prepared in Ex. 1, and powder primer
composition (P-5) was prepared with a blend composition shown as
Ex.5 in Table 1. After conducting primer coating by using the
powder primer composition (P-5), top coating was conducted 6 times,
to obtain a coating test specimen. The same evaluation as in Ex. 1
was conducted, whereby good results were obtained.
Ex. 6 (Comparative Example)
[0110] Powder primer composition (P-6) was prepared with a blend
composition shown as Ex. 6 in Table 2, and a coating test specimen
was obtained. The same evaluation as in Ex. 1 was conducted,
whereby the peel strength was no good, which is considered to be
attributable to that no epoxy resin was used.
Ex. 7 (Comparative Example)
[0111] Powder primer composition (P-7) was prepared with a blend
composition shown as Ex. 7 in Table 2, and a coating test specimen
was obtained. The same evaluation as in Ex. 1 was conducted,
whereby the peel strength was no good, which is considered to be
attributable to that no reactive ETFE was used.
Ex. 8 (Comparative Example)
[0112] Powder primer composition (P-8) was prepared with a blend
composition shown as Ex. 8 in Table 2, by using, as a powder made
of an epoxy resin, powder (EP-3) made of an epoxy resin with an
average particle size of 67 .mu.m, obtained by freeze-crushing
epoxy resin 1001 manufactured by Mitsubishi Chemical Corporation
(epoxy equivalent: 475, molecular weight: 900, softening point:
64.degree. C.), and a coating test specimen was obtained. The same
evaluation as in Ex. 1 was conducted, whereby the peel strength
after the hydrothermal resistance test and the alkali resistance
test, was no good, and deterioration of the powder flowability due
to formation of nodules was observed after the storage stability
test.
Ex. 9 (Comparative Example)
[0113] Powder primer composition (P-9) was prepared with a blend
composition shown as Ex. 9 in Table 2, by using, as a powder made
of an epoxy resin, powder (EP-4) made of an epoxy resin with an
average particle size of 56 .mu.m, obtained by freeze-crushing
epoxy resin 1009 manufactured by Mitsubishi Chemical Corporation
(epoxy equivalent: 2,850, molecular weight: 3,800, softening point:
144.degree. C.), and a coating test specimen was obtained. The same
evaluation as in Ex. 1 was conducted, whereby the peel strength was
low.
Ex. 10 (Comparative Example)
[0114] Powder primer composition (P-10) was prepared by increasing
the blend amount of powder EP-1 made of an epoxy resin with a blend
composition shown by Ex. 10 in Table 2, and a coating test specimen
was obtained. The same evaluation as in Ex. 1 was conducted,
whereby since the powder flowability was low, coating
irregularities were observed at the time of coating the primer
layer. Further, deterioration of the powder flowability due to
formation of nodules was observed after the storage stability
test.
Ex. 11 (Comparative Example)
[0115] With a blend composition shown as Ex. 8 in Table 2, mixing
of the reactive EFTE powder and the powder made of an epoxy resin,
was carried out for 10 minutes by means of a Henschel mixer. The
temperature of the powder during mixing rose to 70.degree. C.,
whereby formation of nodules in the mixture was so much that primer
coating was impossible.
TABLE-US-00001 TABLE 1 Materials, items Unit Ex. 1 Ex. 2 Ex. 3 Ex.
4 Ex. 5 No. of primer P-1 P-2 P-3 P-4 P-5 Blend ratios in Reactive
ETFE-1 Parts by mass 95 90 85 90 primer Reactive ETFE-2 Parts by
mass 95 composition EP-1 Parts by mass 5 10 15 5 EP-2 Parts by mass
10 EP-3 Parts by mass EP-4 Parts by mass Total Parts by mass 100
100 100 100 100 Blend Bulk density g/cc 0.66 0.64 0.61 0.65 0.58
composition of Angle of repose .degree. 45 47 49 47 48 primer
Average particle size .mu.m 39 38 37 39 11 Rank of storage
stability A A A A A Primer coating Application times Times 1 1 1 1
1 Coating thickness .mu.m 34 36 38 42 22 Rank of appearance A A A A
A Top coating Type of ETFE Non- Non- Non- Non- Non- reactive
reactive reactive reactive reactive ETFE-1 ETFE-1 ETFE-1 ETFE-2
ETFE-1 Application times Times 3 3 3 3 6 Coating thickness .mu.m
370 380 360 390 610 Rank of appearance A A A A A Peel strength
Initial N/cm 71.9 77.5 81.0 62.2 68.6 Rank A A A A A Hydrothermal
resistance N/cm 55.2 52.1 47.2 50.4 62.2 Rank A A A A A Alkali
resistance N/cm 59.1 55.6 61.1 56.8 64.0 Rank A A A A A
TABLE-US-00002 TABLE 2 Unit Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Primer
No. P-6 P-7 P-8 P-9 P-10 composition No. Blend ratios in Reactive
ETFE-1 Parts by mass 100 90 95 70 primer Non-reactive ETFE-1 95
composition EP-1 Parts by mass 5 30 EP-2 Parts by mass EP-3 Parts
by mass 10 EP-4 Parts by mass 5 Total Parts by mass 100 100 100 100
100 Properties of Bulk density g/cc 0.69 0.68 0.65 0.68 0.40 primer
Angle of repose .degree. 42 47 55 44 61 Average particle size .mu.m
40 73 43 41 35 Rank of storage stability A A C nodules A C nodules
are formed are formed Primer coating Application times Times 1 1 1
1 1 Coating thickness .mu.m 42 52 43 45 51 Rank of appearance A A C
slight A D substantial thickness thickness irregularities
irregularities occurred occurred Top coating Type of ETFE Non- Non-
Non-reactive Non- Non-reactive reactive reactive ETFE-1 reactive
ETFE-1 ETFE-1 ETFE-1 ETFE-1 Application times Times 3 3 3 3 3
Coating thickness .mu.m 370 380 390 380 450 Rank of appearance A A
C slight air A D substantial bubbles air bubbles observed in
observed in the primer the primer layer layer Peel strength Initial
N/cm 25.8 32.0 55.2 34.2 36.2 Rank C C A C C Hydrothermal
resistance N/cm 8.1 25.5 23.5 15.6 28.6 Rank D C C D C Alkali
resistance N/cm 4.6 16.1 35.1 8.3 13.5 Rank D D C D D
[0116] Reactive ETFE-1: average particle size 40 .mu.m
[0117] Reactive ETFE-2: average particle size 10 .mu.m
[0118] Non-reactive ETFE-1: TL-081, manufactured by Asahi Glass
Co., Ltd., average particle size 76 .mu.m
[0119] Non-reactive ETFE-2: Z-8820X, manufactured by Asahi Glass
Co., Ltd., average particle size 45 .mu.m
[0120] EP-1: Epoxy resin 1004 pulverized product, manufactured by
Mitsubishi Chemical Corporation, average particle size 23 .mu.m,
epoxy equivalent 925, softening point 97.degree. C., molecular
weight 1,650
[0121] EP-2: Epoxy resin 1007 pulverized product, manufactured by
Mitsubishi Chemical Corporation, average particle size 28 .mu.m,
epoxy equivalent 1,975, softening point 128.degree. C., molecular
weight 2,900
[0122] EP-3: Epoxy resin1001 pulverized product, manufactured by
Mitsubishi Chemical Corporation, average particle size 67 .mu.m,
epoxy equivalent 475, softening point 64.degree. C., molecular
weight 900
[0123] EP-4: Epoxy resin 1009 pulverized product, manufactured by
Mitsubishi Chemical Corporation, average particle size 56 .mu.m,
epoxy equivalent 2,850, softening point 144.degree. C., molecular
weight 3,800
INDUSTRIAL APPLICABILITY
[0124] The primer composition of the present invention is excellent
in adhesion properties, durability, storage stability and uniform
coating properties, as compared with conventional ETFE primers. The
primer composition of the present invention can be applied to the
surface of a heat resistant substrate such as metal, glass,
ceramics, etc. and is useful as a primer for lining, coating or
surface treatment by a fluoro-resin, particularly by ETFE. The
primer composition of the present invention and a laminate
obtainable by using the primer composition of the present
invention, may be used for, for example, various containers, pipes,
tubes, tanks, pipe lines, joints, rolls, autoclaves, heat
exchangers, distillation towers, jigs, bulbs, stirring vanes,
tanker lorries, pumps, casings for blowers, centrifugal separators,
kitchen utensils, etc.
[0125] This application is a continuation of PCT Application No.
PCT/JP2014/082312, filed on Dec. 5, 2014, which is based upon and
claims the benefit of priority from Japanese Patent Application No.
2013-255660 filed on Dec. 11, 2013. The contents of those
applications are incorporated herein by reference in their
entireties.
* * * * *